The body control module (BCM) is capable of accomplishing multiple body control functions. Components directly connected to the BCM are controlled by the BCM outputs. The BCM can control its outputs based on input information it obtains from sensors and switches that are directly connected to the BCM, or by receiving information from other vehicle systems connected to the class 2 serial data link. The BCM evaluates this information and controls certain body systems by commanding an output on or off.

The BCM is also capable of commanding other vehicle systems to control functions that are not directly wired to and/or controlled by the BCM. The BCM accomplishes this task by sending specific messages on the class 2 serial data link. The vehicle system capable of performing such function will respond to the BCM message.

The BCM controls/monitors the following functions:

The BCM provides the following audible control functions. Some audible control functions may be controlled by other systems through the class 2 serial data link:

Refer to Audible Warnings Description and Operation in Instrument Panel, Gages, and Console for more information.

The BCM provides the following indicator control functions through the class 2 serial data circuits. Some indicator control functions may be controlled by other systems through the class 2 serial data link:

Refer to Instrument Cluster Description and Operation and Indicator/Warning Message Description and Operation in Instrument Panel, Gages, and Console for more information.

The BCM provides the following interior lighting functions. Some interior control functions may be controlled by other systems through the class 2 serial data link:

Refer to Interior Lighting Systems Description and Operation in Lighting Systems for more information.

The BCM provides the following exterior lighting control functions. Some exterior lighting control functions may be controlled by other systems through the class 2 serial data link:

Refer to Exterior Lighting Systems Description and Operation in Lighting Systems for more information.

The BCM provides the following power/automatic door lock control functions. Some door lock control functions may be controlled and/or sent by other systems through the class 2 serial data link:

Refer to Power Door Locks Description and Operation in Doors for more information.

The BCM provides the following keyless entry control functions. Some keyless entry control functions may be controlled and/or sent by other systems through the class 2 serial data link:

Refer to Keyless Entry System Description and Operation in Keyless Entry for more information.

The BCM provides the following content theft deterrent control functions. Some content theft deterrent control functions may be controlled and/or sent by other systems through the class 2 serial data link:

Refer to Theft Systems Description and Operation in Theft Deterrent for more information.

The BCM provides personalization of vehicle functions which allow BCM features to be personalized based on driver preferences. The following vehicle functions may be personalized:

Refer to the following Personalization Description and Operation in Personalization for more information on how to set personalized options.

On vehicles that have several control modules connected by serial data circuits, one module is the power mode master (PMM). On this vehicle the PMM is the body control module (BCM). The PMM receives 3 signals/circuits from the ignition switch. These are the Unlock (IGN0), Run/Crank (IGN1) and Accessory (ACC) ignition switch signals/circuits.

To determine the correct power mode the PMM uses:

The chart below indicates the modes detected and transmitted by the PMM:

Since the operation of the vehicle systems depends on the power mode, there is a fail-safe plan in place should the PMM fail to send a power mode message. The fail-safe plan covers those modules using exclusively serial data control of power mode as well as those modules with discrete ignition signal inputs.

Serial Data Messages

The modules that depend exclusively on serial data messages for power modes stay in the state dictated by the last valid PMM message until they can check for the engine run flag status on the serial data circuits. If the PMM fails, the modules monitor the serial data circuit for the engine run flag serial data. If the engine run flag serial data is True, indicating that the engine is running, the modules fail-safe to "RUN". In this state the modules and their subsystems can support all operator requirements. If the engine run flag serial data is False, indicating that the engine is not running, the modules fail-safe to "OFF-AWAKE". In this state the modules are constantly checking for a change status message on the serial data circuits and can respond to both local inputs and serial data inputs from other modules on the vehicle.

Discrete Ignition Signals

Those modules that have discrete ignition signal inputs also remain in the state dictated by the last valid PMM message received on the serial data circuits. They then check the state of their discrete ignition input to determine the current valid state. If the discrete ignition input is active, B+, the modules will fail-safe to the "RUN" power mode. If the discrete ignition input is not active, open or 0 voltage, the modules will fail-safe to "OFF-AWAKE". In this state the modules are constantly checking for a change status message on the serial data circuits and can respond to both local inputs and serial data inputs from other modules on the vehicle.

The BCM provides the following electrical power management functions. Some power management functions are controlled by working with other systems through the class 2 serial data link: